Hydrology | Center for Urban Water, Sri Lanka

Hydrology

 Two hydrological models are being tested for forecasting accuracy. Later as new models became available they will be incorpoarated in the system. 

  • HEC-HMS
  • SHER - Similar Hydrological Element Response model

HEC-HMS

Hydrologic Engineering Center – Hydrologic Modeling System (HEC – HMS). was calibrated wtih rainfall event in November 2005, and  extreme events in April–May 2008, May–June 2008, and May 2010 were used to assess model performance in event modeling. The same calibrated direct runoff and baseflow parameters were then used for the continuous hydrologic modeling. However, the Green and Ampt infiltration loss method was used to estimate infiltration loss in event based modeling where as a 5–layer soil moisture accounting loss method was employed in continuous modeling. The study confirmed the potential of HEC–HMS for flood forecasting in Kelani River basin.

SHER

SHER(Similar Hydrologic Element Response)model mainly consists of sub models of surface, subsurface and aquifer. In the surface model, kinematic wave equation is used for surface flow computations. In subsurface model, the one dimensional Richard’s equation is used. The Darcy’s flow is assumed in the aquifer model. 

This model was originally applied to urban basins. However, the model was successfully applied to several mountainous basins in the recent years.